Phosphoproteomic analysis of CD2 signaling reveals an AMPK-dependent targeted granule secretion in human cytotoxic T cells

ABSTRACT: The in-depth analysis of co-stimulatory signaling enhancing the activity of cytotoxic T cells represents a major approach towards the development of immunotherapies. Here we describe that CD2 co-stimulation plays a critical role in the functioning of human cytotoxic T cells (CTLs). We found that CD2 promotes the formation of functional immune synapses by orchestrating the polarization of lytic granules towards the synaptic interface. To broadly explore the CD2 signaling network, we undertook an analysis of protein phosphorylation in CD2-stimulated CTLs, which revealed 549 unique CD2-regulated phosphorylation events in 373 proteins. CD2 stimulation elicited an intricated network of signaling events participating in the regulation of T cell metabolism, vesicular trafficking, autophagy, cell polarity and cytoskeleton organization. We further show that a functionally critical node of this network is the AMP-activated protein kinase (AMPK), which regulates granule polarization at the CTL synapse. Polarized trafficking of granules is driven by the concerted action of TAK1/LKB1/CamKK2 kinases, which locally activate AMPK enriched on CTL lysosome membranes, illustrating a novel functional cross-talk between vesicular compartments in CTLs. Our results thus establish CD2 signaling as key for regulating targeted granule secretion in CTLs and reveal an AMPK-dependent mechanism to explain how AMPK-activating drugs boost anti-tumour CTL activity.

INSTRUMENT(S): Orbitrap Fusion Lumos

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): B Cell, T Cell, Blood

DISEASE(S): Disease Free

SUBMITTER: Roman Fischer  

LAB HEAD: Roman Fischer

PROVIDER: PXD013840 | Pride | 2020-04-28

REPOSITORIES: Pride